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Valve drive apparatus of internal-combustion engine

a technology of valve drive and internal combustion engine, which is applied in the direction of machines/engines, electrical control, output power, etc., can solve the problems of insufficient functioning of catalysts, low temperature of exhaust gas, and interference of intake valves with pistons, so as to enhance the effect of internal egr

Inactive Publication Date: 2005-03-31
MITSUBISHI FUSO TRUCK AND BUS CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

"The invention is a valve drive apparatus for an internal-combustion engine that enhances the effect of an internal EGR (exhaust gas recirculation). The apparatus includes an exhaust valve drive mechanism that can change the timing of the exhaust valve, and a control device that controls the exhaust valve drive mechanism to release the exhaust valve during the intake stroke in an EGR mode. This allows for better adjustment of the amount of exhaust gas mixed in the intake air, resulting in increased EGR. The control device can also set the amount of valve lift of the intake valve in the EGR mode to be smaller than the normal mode, which further enhances the effect of EGR. The invention simplifies the structure of the valve drive apparatus and reduces the amount of intake air flow during EGR, resulting in even greater enhancement of the EGR effect."

Problems solved by technology

While the engine is running, at the time of idling or other low load time, the temperature of exhaust gas is low, and the catalyst does not function sufficiently.
However, since the intake valve is released in the vicinity of the top dead center of a piston, when the overlap amount is increased, the intake valve interferes with the piston.
Therefore, by the increase of the overlap amount alone, the EGR is limited, so that it is hard to enhance the effect of the internal EGR.

Method used

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  • Valve drive apparatus of internal-combustion engine
  • Valve drive apparatus of internal-combustion engine
  • Valve drive apparatus of internal-combustion engine

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first embodiment

[0044] (First Embodiment)

[0045] A first embodiment of the invention will be described below while referring to FIGS. 1 to 12.

[0046]FIG. 1 shows essential parts of an internal-combustion engine according to the invention. This is a reciprocating engine, and is configured to generate a driving force by repeating the cycle consisting of intake, compression, expansion, and exhaust strokes. More specifically, the diagram shows a valve drive apparatus of a diesel engine in which plural cylinders (not shown) are arranged along a cam shaft. FIG. 3 shows a section of an exhaust side of the valve drive apparatus (the section in the direction of arrow X in FIG. 1).

[0047] In FIG. 1, reference numeral 1 denotes an engine body. The engine body 1 is composed of a cylinder block 2 and a cylinder head 3. The cylinder block 2 incorporates plural cylinders (not shown) arranged in the lateral direction. The cylinder head 3 is connected to the head of the cylinder block 2. Each cylinder in the cylinde...

second embodiment

[0081] (Second Embodiment)

[0082] A second embodiment of the invention will be shown in FIGS. 13 to 15. In this embodiment, in order to further enhance the effect of the internal EGR, in addition to the exhaust valve drive mechanism 20 for enabling to release the exhaust valve 4 during the intake stroke, an intake valve drive mechanism 70 is provided, which is intended to vary the amount of valve lift of the intake valve 5 in the intake stroke. By using this intake valve drive mechanism 70, it is controlled, in the EGR mode, such that the amount of valve lift of the intake valve 5 is smaller than the amount of valve lift in the normal mode.

[0083] More specifically, a mode selection mechanism 40a, which is similar to the mode selection mechanism 40 in the first embodiment, is assembled in the cam shaft 14 for intake and a rocker shaft 71 for intake as shown in FIG. 13.

[0084] The components of the mode selection mechanism 40a are basically same as components of the mode selection mec...

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Abstract

The valve drive apparatus of the invention comprises an exhaust valve drive mechanism capable of changing an open / close timing of an exhaust valve, and a control device which controls the exhaust valve drive apparatus so as to release the exhaust valve during an intake stroke, independently of an exhaust stroke, in an EGR mode. Preferably, the exhaust valve drive mechanism comprises a first exhaust cam which defines the exhaust valve releasing timing and the amount of valve lift in the exhaust stroke, and a second exhaust cam which defines the exhaust valve releasing timing and the amount of valve lift during the intake stroke. In an normal mode, the displacement of the first exhaust cam is transmitted to the exhaust valve, and in the EGR mode, the displacement of the second exhaust cam is transmitted to the exhaust valve, in addition to the displacement of the first exhaust cam.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-340835, filed Sep. 30, 2003, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a valve drive apparatus of an internal-combustion engine for realizing internal EGR. [0004] 2. Description of the Related Art [0005] A reciprocating engine (internal-combustion engine) mounted on an automobile performs EGR (exhaust gas recirculation), that is, to recirculate part of engine exhaust gas to the intake side, as required, in order to improve the composition of exhaust gas and activate the catalyst earlier. Recently, as the EGR, aside from an external EGR which requires relay pipes around the engine, an internal EGR not requiring such pipes comes to be used. In the internal EGR, out of the engine combustion cycles (intak...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): F01L1/34F01L1/26F01L13/00F02D13/02F02D21/08F02D41/00F02M25/07
CPCF01L1/267F01L13/0036F01L2105/00F02D13/0211Y02T10/18F02D13/0273F02D41/006F02D2041/001F02M25/0752F02D13/0246F02M26/01F01L2305/00Y02T10/12F01L1/34
Inventor DAIGO, YASUNORIMAEKAWA, MASAHIROKAWATANI, TORUHORIUCHI, MANABUNAKAJIMA, SATOSHIKAWAMOTO, KOICHI
Owner MITSUBISHI FUSO TRUCK AND BUS CORPORATION